Synthesis gas, also termed syngas, may be generated by a gasification of carbonaceous feedstocks such as biomass, coal, petroleum coke or other carbon-rich feedstocks using oxygen or air and steam at elevated temperature and pressure. In gasification or other synthesis gas generation processes operated at low temperatures, in addition to other sulphur compounds, thiophene may be present in the resulting synthesis gas. Thiophene is a potent catalyst poison and levels as low as 1 to 5 ppb by volume gas can pose a problem for downstream catalytic processes.
EP1476246 (A1) discloses a process for the removal of sulphur compounds, particularly hydrogen sulphide (H2S) and carbonyl sulphide (COS), from synthesis gas containing hydrogen, carbon dioxide and steam comprising contacting the synthesis gas at a maximum contact temperature of 100° C. with an absorbent comprising pre-reduced Cu/ZnO compounds.